X-Message-Number: 13442
Date: Thu, 30 Mar 2000 21:33:59 -0800 (PST)
From: Doug Skrecky <>
Subject: peg might be a useful addition to vitrification solutions

(note: peg 200 can penetrate tissue)

Citations: 1-2
  Sutton RL.
  MRC Medical Cryobiology Group, University Department of Surgery, Cambridge,
  United Kingdom.
  Critical cooling rates for aqueous cryoprotectants in the presence of sugars
  and polysaccharides.
  Cryobiology.  29(5):585-98, 1992 Oct.
  The technique of isothermal emulsion differential scanning calorimetry was
  used to determine time-temperature-transformation (TTT) curves for aqueous
  glycerol and butane-2,3-diol in the presence of various polysaccharides and
  sugars. The critical cooling rate required to avoid the crystallization of
  ice in these solutions was then calculated from the experimental TTT curves.
  The polysaccharides used in this study included starch hydrolysis products
  and dextrans of various molecular weights. The sugars used here were sucrose,
  glucose, trehalose, and raffinose. The results show that the critical cooling
  rates of butane-2,3-diol and glycerol are reduced by varying amounts by the
  addition of such materials but that the reduction is not as great as is
  achieved by the addition of polyethylene
  glycol with a molecular weight of 400.

  Banker MC.  Layne JR Jr.  Hicks GL Jr.  Wang T.
  Department of Surgery, University of Rochester, N.Y. 14642.
  Freezing preservation of the mammalian heart explant. III. Tissue dehydration
  and cryoprotection by polyethylene glycol.
  Journal of Heart & Lung Transplantation.  11(4 Pt 1):619-23, 1992 Jul-Aug.
  Isolated rat hearts perfused with hyperosmotic Krebs-Henseleit buffer
  containing 60 mmol/L NaCl lose 10% of their tissue water. Perfusion of the
  rat hearts with Krebs-Henseleit buffer containing
  polyethylene glycol 8000 caused a
  concentration-dependent reduction in tissue water. In a study of the effect
  of different cryoprotectants on cardiac preservation, isolated rat hearts
  were flushed with a cardioplegic solution (CP-14), or CP-14 with either 50
  mmol/L glycerol (CP-15), or 5% polyethylene
  glycol (CP-16) and frozen at -1.4 degrees C for 5 hours.
  Thawed hearts were reperfused in working mode to assess function. There was
  no recovery in CP-14 hearts. Hearts treated with CP-15 recovered 39.3% +/-
  2.9% (mean +/- SEM) of control cardiac output. CP-16 boosted the recovery of
  cardiac output to 54.4% +/- 5.7% (p less than 0.05 vs CP-15). Glycerol
  significantly reduced tissue ice content; PEG further decreased the ice
  content to 31.7% +/- 0.6%, which was distinctively lower than that in CP-14
  (44.7% +/- 1.1%) and in CP-15 hearts (34.6% +/- 1.1%). Tissue water content
  of CP-14 and CP-15 hearts was similar (3.83 and 3.87 gm H2O/gm dry weight).
  Polyethylene glycol reduced the tissue
  water content to 3.24 +/- 0.04 gm H2O/gm dry (p less than 0.01 vs CP-14 and
  CP-15 by ANOVA). Thus both glycerol and polyethylene
  glycol offered cryoprotection to the heart explant by
  reducing tissue ice formation. Polyethylene
  glycol was superior to glycerol by dehydrating myocardial
  tissue and further minimizing freezing damage.

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